1. Department of Otorhinolaryngology—Head and Neck Surgery, Konkuk University School of Medicine, Daejeon, Korea
2. Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul, Daejeon, Korea
3. Department of Otolaryngology—Head and Neck Surgery, Cancer Research Institute, Research Institute for Medical Sciences, Chungnam National University College of Medicine, Daejeon, Korea